The UCLA-CMCR Animal Core provides a full support fro animal experiments in all Full Projects and many Pilot Projects. The Core is a self-contained, fiscally independent, strict barrier facility that breeds and maintains, at a low cost, the highest possible quality gnotobiotic mice with a defined microbiological flora. It maintains breeding colonies of multiple immune competent, immune deficient, and transgenic strains that allow definitive studies on DNA repair, DNA damage response, cytokine, Toll-like receptor and other pathways that are relevant to radiation effects. In the past funding period, an average of 5,500 mice per year were used by full projects and it contributed greatly to the success of the UCLA-CMCR. The facility has an AEC cesium source 'en suite' with jigs enabling whole and partial body irradiations to be performed. X-ray and cobalt radiation machines are also available. It provides assistance with animal Irradiations on an as needed basis. It has a level II Biohazard facility and can accommodate studies on gene transfer, radioisotopes, and pathogens and provide assistance with such studies. The Core assists investigators in obtaining IACUC approval, monitors compliance and animal health, as well as providing training and advice for investigators in animal handling, procedures, the design and performance of radiation experiments and analysis and interpretation of results. This resource is available to all members of the UCLA-CMCR and others outside of UCLA on a recharge basis. These activities can be fully integrated because the facility is under the direct control of Dr. McBride who has the power to allocate space and resources to the CMCR, whose investigators receive priority. The Core brings great expertise in the responses of most normal tissues to radiation, in DNA repair, in genetics, and in immunity. It provides a variety of models to address the product potential of mitigators of radiation tissue damage and the pathways by which they may operate. It will perform a vital function in integrating the projects within the CMCR and in standardizing the information that is derived from individual animal experimentation. In so doing, it will give added value to the CMCR.